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Out of sequence

16 replies [Last post]
Wed, 2009-06-24 01:42
Rex Lorenzo
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Dear Planning expert,

Would you mind to advice how you manage the out of sequence in your current schedule, ie a baseline schedule with Finish to start relationship but the later was started before completion of predecessor.
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Tue, 2019-06-11 13:12
#1
Rafael Davila
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After ten years an old discussion/coffin was opened.

Anyway, such proposed shortcuts are not necessarily a good idea, some can lead to open ended activities and nothing is said about adjusting lag, a common cause for out-of-sequence performance. Get the PM involved in correcting the logic to ensure that the project schedule matches the current planning. 

Out-Of-Sequence Progress - Warner

When removing out-of-sequence progress, the Project Manager should be involved in the changes made since it will require logic changes. In many cases the schedule can be adjusted to satisfy the out-of-sequence work through the use of a finish to finish (FF) relationship with a proper lag, to be determined by the Project Manager. Alternatively an additional schedule activity can be added that divides the activity into two parts. In the example above, ‘Excavate Footings’ could become two separate activities, one a predecessor to the start of concrete placement. This will remove the out-of-sequence progress and bring the schedule back into compliance with a specification that demands no out-of-sequence progress, and most importantly this will retain the actual schedule logic intent to better reflect reality. There are other ways to handle the out-of-sequence progress, but these methods seem to be the most preferred within the industry.

Out-Of-Sequence Progress - TRAUNER

Ultimately, it’s our recommendation that instead of relying on the Progress Override and Actual Dates options to deal with activities that progress out of sequence, owners should specify the use of the Retained Logic option and require contractors to address activities that progress out of sequence on an activity-by-activity basis as it occurs and to make appropriate changes to the schedule logic to ensure that the project schedule matches the current construction.

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Tue, 2019-06-11 11:34
#2
Ali Osama
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Read this article about....How to solve out of sequence activities in P6

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Sat, 2009-07-11 21:01
#3
Rafael Davila
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Rex

Also remember to backup your database, not only your PST or individual job files, if not you might lose some data stored in the database but not under the individual job files.

http://primavera.zxlm.cn/kb/prim54984

You can copy the text and pictures with your cursor selection tool then copy it into MS Word and convert into a PDF file any reference you find useful.

http://rapidshare.com/files/254885460/P6-Backup___Restore_SQL_2005_Expre...

As I told you I am not a P6 user but I tried it for a few weeks. It work its database(s) in a different way P3 does. P3 stores every job or group into its own separate database P6 uses a single database for all your jobs although you can create other databases and keep a separate set of jobs. If you read the reference you will figure it out how to create another database using an existing one and renaming it.

Best regards
Rafael
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Sat, 2009-07-11 19:46
#4
Rex Lorenzo
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Rafael,

You’re right, I export the first version (updated one) then re import the data in 2nd version. With some trial and error there are import configuration that need to be taken to suit what we wanted. Bear in mind to keep a backup of your file before importing data.

I’m newly migrated in P6 and I’m not sure if there’s an easier one to import update to another version. With more than two thousand of activities of our program, at least I saved 2~5 hours a week.

Regards,
Rex
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Sat, 2009-07-11 06:36
#5
Rafael Davila
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Rex,

I do not have P6, my idea was to look for Primavera Post Office/Mail within P6, if available. I am not sure if you used Primavera Post Office/ Mail or not. I believe that maybe you figured out yourself another procedure if P6 does not have the Primavera Post Office functionality available in P3 and SureTrak.

Probably if P6 lacks Primavera Post Office you exported your updated file to a PST file and imported it back to update your second version. I have never done that under P3 but P6 as its own ways.

I would be good if you can briefly expose how you did it so others can benefit from a clever solution you figured out yourself.

Even if you used another method different to Post Office let me know if Post Office functionality is available under P6, I don’t have P6 it but interested in knowing.

Best regards,
Rafael
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Fri, 2009-07-10 04:13
#6
Rex Lorenzo
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Rafael,

Though your advice is a general one, I try to figure out by trial and error and it work.

You’re a real guru.

Many thanks.

Rex
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Fri, 2009-06-26 08:04
#7
Rafael Davila
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Rex:

Regarding your posting no4; I have been in need of having two schedule versions of a job, one the contractual version which at times the Owner’s rep does not allow you to change until pending change orders are finally negotiated and approved.

For this purpose I use Primavera Post Office available for SureTrak as well as for P3, I can update two versions with only a few clicks of the mouse. If your revised schedule has extra activities then use this one as the basis for your Post Office Updating. Remember Post Office will only update actual Dates and either %complete or remaining duration it won’t mess with the logic.

Being P6 a Primavera product I would not be surprised if they provide the same functionality within P6.

You will have to figure it out how P6 handles or identifies the specific job name to update. In Suretrak the updating ask you to select to which project you will update using the data, it can be another version.

The good thing about Post Office is that the updater can update the job without having Surtrak or P3, just the schedule printouts, suspect the same for P6.

Maybe you can figure out a way to use this functionality to transfer update data within your computer, you being the sender and recipient of Post Office.

Best regards,
Rafael

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Thu, 2009-06-25 10:06
#8
Gary Whitehead
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That is true, but i think you can set this limit by specifying how much over-allocation of resources you will allow.

Best way for productivity rates is to measure them! If you are doing a series of 5 week projects with very similar activities, you should be able to get a good set of data quite quickly.
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Thu, 2009-06-25 09:25
#9
K Z
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P6 has it, but I think relying on the software to level resources may not produce a desirable result. Because if you programme the software to level within a certain float, then there will be a limit to how the software can level the schedule.
What do you think is the best way forward to get the productivity rates for the crew?
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Thu, 2009-06-25 08:53
#10
Gary Whitehead
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KZ,

I’ve not used levelling in P5/6, but there should be an option to ensure total float doesn’t drop below zero. Instead, it will over-allocate resources as required (but in the most efficient way) to ensure you still hit your deadline.
(NB: I wouldn’t be suprised if there’s also an option to get it to level 2 projects sharing resources but with different completion dates (eg 2 trains) simultaneously)

Once it’s run, you should have the most efficient sequence of work & allocation of resources to achieve your objective.

If and when you get additional scope added, enter it into the programme, re-run the levelling, and the difference in resource requirements to your previous version is the additional resources required.

My advice is save a copy of your project, and have a play with the resource levelling function.
Make sure you sense-check the new programme each time you level, as it can come up with solutions that look good on paper, but not in the real world.
Also, you’ll need to have a good handle on the productivity rates of your crews to get the best out of resource levelling

Your next challenge will be to get the site manager to pay attention to your programmes, or else it’s all a bit of a waste of time!

Cheers,

G
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Thu, 2009-06-25 04:54
#11
K Z
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Thanks Gary,
I am not conversant with resource leveling, because in my experience i have not worked on a resource levelled project.But my present programme is resource loaded with skill set eg; vehicle builders, electricians or testers.
Right now the Site person in charge drives the job without reference to our schedule. What happens then is a situation whereby we meet our contractual time obligation but we spend more hours than our contractual man -hours estimate. I have read books about resource leveling but I have not done it practically. I know resource leveling is a process whereby one has to level the resource usage to the maximum allowable limit (say 8 hours/day), sometimes achieving this could mean extending the duration of the project, in my situation how would resource levelling help (knowing my time constraint is of essence)?
How can this concept, also help me estimate what additional resource I require?
I just want to understand it from first principle, so that the philosophy can be transferred to my DNA!! Take me to another level in planning!!
Once again Gary thank you fo ryour prompt reply.
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Thu, 2009-06-25 03:52
#12
Gary Whitehead
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RL:

Unless it is a contractual condition that you are not allowed to change the sequence of work without submitting a revised plan for approval, I would advise keeping the ACP as an (unprogressed) baseline, and just make the required logic changes & updates to your current programme. I don’t like the idea of having 1 programme for the client, and 1 for the job -Open to abuse, and if any inconsistencies occur in update between the two projects you can quickly loose sight of what actually happened when.

If you do have to progress both versions of the programme, there is probably a function that would let you export progress from 1 programme into excel, and import it into the other (assuming activity IDs are the same), but someone who uses P6 more than I would have to tell you how to do it.

KZ:
In these circumstance, I’m not sure it’s worth having the logic in the first place!

Sounds like you do not have a resource loaded & levelled programme, and are using logical relationships to represent limited resources instead?
If so, I would suggest going down the resource levelling route and only using logical relationships to define the mandatory sequence of activities. Out of Sequence working then should disapear (or if it doesn’t, you know it’s something to worry about rather than just a pain in the neck for the planner), and hopefully you would generate a schedule you can achieve in the 5 week timeframe without having to crash the schedule at the end. (NB: You can use a dummy resource to represent space constraints)
If extra work is added, do you still have to achieve the increased scope within the same 5 weeks? Presumably this requires additional resources? If so a resource levelled plan will also help you quikly estimate what additional resources you will require.

Out of Sequence working only affects Earned value in the sense that the work you are doing ahead of schedule may not have the same value as the work that is pushed back. It could be a positive or negative impact and if this is happeneing a lot, will probably even out over the project. The overiding factor in your earned value will still be productivity (work Arising will oviously also have a big impact on earned value vs planned)

Cheers,

G
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Thu, 2009-06-25 01:57
#13
K Z
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I am working on a train refurbisment project. We are contracted to deliver the train in 5 weeks and at every point in time we have two trains in our shoop floor.
We are constrained by space,as one of the trains has to be in the rubb tent for painting, we are also constrained by resources, as a lot of the workers are still in a learnig curve, not forgeting the time constraint (5 weeks).
These circumstances has made it impossible to stick to the logic of our schedule, consequently I always expect an out of sequence progress, because close to the 5 weeks delivery day all our resources concentrate on the train that is 5 weeks old, so as to meet the contract delivery date.Another problem we encounter is work Arising (work that we did not anticipate), although the clients pay for such work, it impacts on our timescale there affects our logical plan.
I have tried to change the logic more than 10 times but the exigencies takes precedence over logic.
In these circumstances do you think it is worth changing the logic?
I use earn value analysis; will this out of progress affect my earn value results, especially SV and SPI

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Wed, 2009-06-24 04:32
#14
Rex Lorenzo
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Hi Arnold/Gary,

Thanks for your insight. That’s what I did with our schedule, changing the right logic to meet the site condition but our contract manager suggested that we update a separate one retaining the approved construction program (ACP) to anticipate a future delay issues.

To minimize my time in updating, do you have an advice to update the current one with modified logic and transfering update with ACP retained logic?

Regards,
RL


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Wed, 2009-06-24 03:08
#15
Gary Whitehead
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Firstly you need to understand why the work was done out of sequence. There are 2 broad reasons this could happen:

1) The baseline schedule logic was incorrect. In this case, correct the broken logic in your current programme as Arnold suggested. I would advise keeping notes on what you have changed from the baseline, when, and why. This may help you in possible future EOT / LD discussions.
You should also try to understand why the baseline logic was incorrect in the first place so it doesn’t happen again.

2) The baseline schedule was correct, but for some reason the work happened in the incorrect seqnece on site. In this case, the most important thing is to understand the implications for the rest of the project on this OOS work. It could lead to something very serious like introducing oil into a new refinery before the fires safety systems have been commissioned, or it could be something relatively trivial like some of the plastering will have to be redone because the plumming has not yet been installed.
You also need to understand why these tasks where performed out of sequence so it doesn’t happen again.

Cheers,

G
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Wed, 2009-06-24 02:48
#16
Arnold Puy
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Hi Rex,

First of all welcome to Planning Planet.

Out-of-sequence happens when the logic in a plan can be broken when tasks have started or finished before their predecessors.

I suggest that any broken logic is removed or corrected to ensure the project schedules as expected.

Consider fixing the broken logic by FS to SS relationship either changing or removing the link.

Regards,

Arnold
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